| Attributs | Valeurs |
|---|
| type
| |
| Is Part Of
| |
| Subject
| |
| Title
| - New Benchmark for Water Photooxidation by Nanostructuredα-Fe2O3 Films
|
| has manifestation of work
| |
| related by
| |
| Author
| |
| Abstract
| - Thin films of silicon-doped Fe2O3 were deposited by APCVD (atmospheric pressure chemicalvapor deposition) from Fe(CO)5 and TEOS (tetraethoxysilane) on SnO2-coated glass at 415 °C. HRSEMreveals a highly developed dendritic nanostructure of 500 nm thickness having a feature size of only 10−20 nm at the surface. Real surface area determination by dye adsorption yields a roughness factor of 21.XRD shows the films to be pure hematite with strong preferential orientation of the [110] axis vertical to thesubstrate, induced by silicon doping. Under illumination in 1 M NaOH, water is oxidized at the Fe2O3 electrodewith higher efficiency (IPCE = 42% at 370 nm and 2.2 mA/cm2 in AM 1.5 G sunlight of 1000 W/m2 at 1.23VRHE) than at the best reported single crystalline Fe2O3 electrodes. This unprecedented efficiency is in partattributed to the dendritic nanostructure which minimizes the distance photogenerated holes have to diffuseto reach the Fe2O3/electrolyte interface while still allowing efficient light absorption. Part of the gain inefficiency is obtained by depositing a thin insulating SiO2 interfacial layer between the SnO2 substrate andthe Fe2O3 film and a catalytic cobalt monolayer on the Fe2O3 surface. A mechanistic model for waterphotooxidation is presented, involving stepwise accumulation of four holes by two vicinal iron or cobaltsurface sites.
|
| article type
| |
| is part of this journal
| |
